As far as stopping password reuse, I recall seeing a while ago on HN a "joke" tool to do just that, by attempting to log into a bunch of services with the email

As far as stopping password reuse, I recall seeing a while ago on HN a "joke" tool to do just that, by attempting to log into a bunch of services with the email / pass provided. I believe it was called Evilpass. I personally prefer the "zxcvbn" method, which is why I wrote a Java library for my company inspired by it called nbvcxz.